FIR filter design with Julia

Matti Pastell

21th April 2016

Introduction

This an example of a julia script that can be published using Weave. The script can be executed normally using Julia or published to HTML or pdf with Weave. Text is written in markdown in lines starting with "#' " and code is executed and results are included in the published document.

Notice that you don't need to define chunk options, but you can using #+. just before code e.g. #+ term=True, caption='Fancy plots.'. If you're viewing the published version have a look at the source to see the markup.

Design Lowpass FIR filter

Designing a lowpass FIR filter is very simple to do with DSP.jl, all you need to do is to define the window length, cut off frequency and the window. We will define a lowpass filter with cut off frequency at 5Hz for a signal sampled at 20 Hz. We will use the Hamming window, which is defined as: $w(n) = \alpha - \beta\cos\frac{2\pi n}{N-1}$, where $\alpha=0.54$ and $\beta=0.46$